USNVC

The US National Vegetation Classification (USNVC) provides a national, conceptual framework for classifying, inventorying, and studying both cultural and natural vegetation of the U.S. It provides a common language for the effective management and conservation of plant communities.

The USNVC federal Standard is a process standard. The standard itself does not contain a formal set of classification units but rather outlines the process by which such units are to be described, peer reviewed, and maintained through various data-management and web tools. This means that the classification is dynamic, subject to change as vegetation scientists revise or newly describe vegetation types in the United States.

The vision for the Standard was that it would be:

Useful for conservation and resource management
Focused on classifying existing vegetation
Hierarchical, with upper levels based on physiognomy and lower levels based on floristics
Inclusive of both cultural and natural vegetation types
Built from publicly available plot data whenever possible
Revised through a peer review process

The hierarchy for the cultural types of the standard relies heavily on existing classification systems (FGDC 2008). The proposed pilot classification for the upper levels of the cultural hierarchy are based on the National Land Cover Dataset (USGS 2001) classes, while several of the lower levels are based on the Natural Resources Inventory, the Natural Resources Conservation Service (NRI 2003). The ESA Panel on Vegetation Classification plans to continue to work with the federal agencies to refine the classification of cultural types.

Currently much of the activity of the ESA Panel is focused on implementing a streamlined peer-review process for descriptions at all levels of the hierarchy and developing training and outreach materials for USNVC users.

If you are interested in participating in the review process please contact us.

For more details on these efforts, please see the Projects page.

TO EXPLORE THE CURRENT CONTENT – VISIT THE NVC Hierarchy Browser.

FGDC 2008 National Vegetation Classification Standard, Version 2. Federal Geographic Data Committee – Vegetation Subcommittee. FGDC-STD-005-2008 (Version 2). http://www.fgdc.gov/standards/projects/FGDC-standards-projects/vegetation/NVCS_V2_FINAL_2008-02.pdf
National Resources Inventory (NRI). 2003. Handbook of Instruction for Remote Data Collection, Chapter 13. Land Cover / Use. Natural Resources Conservation Service. USDA, Washington, DC.
U.S. Geological Survey (USGS). 2001. NLCD Land Cover Class Definitions, USGS EROS Data Center, Sioux Falls, South Dakota, URL: http://landcover.usgs.gov/natllandcover.php, last accessed 30 August 2006.

Management and Vision:

The USNVC is managed through a formal partnership between federal land management agencies, the Ecological Society of America (ESA), and NatureServe. These groups work jointly under the Vegetation Subcommittee, a part of the Federal Geographic Data Committee. Together, they are committed to supporting the implementation and maintenance of the USNVC.

The USNVC is driven by this vision:

The Vegetation Classification Standard enables federal agencies to produce uniform statistics about vegetation resources across the nation, facilitates interagency cooperation on vegetation management issues that transcend jurisdictional boundaries, and encourages non-Federal partners to utilize and contribute to a common system when working with their Federal partners.

Structure and Applications

Land management agencies are actively engaged in inventory and monitoring vegetation resources across the nation. However, while vegetation classification is integral to the successful functioning of a variety of groups across all jurisdictional boundaries, no single agency has been tasked with the sole purpose of mapping or describing vegetation in the United States. As a result, many agencies have created their own protocols, resulting in data that is incompatible across jurisdictional boundaries. The USNVC was created to address this need. Its structure is:

Focused on classifying existing vegetation
Hierarchical, with upper levels based on physiognomy and lower levels based on floristics
Inclusive of both cultural and natural vegetation types
Built from publicly available plot data whenever possible
Revised through a peer-review process

The common language provided by the standard increases the return on those individual investments and allows the development of efficient strategies for guiding future work. Furthermore, it is more about more than just plants. The classification supports wildlife conservation and forest fire management. Some activities supported by the USNVC are:

Modeling and mapping wildlife habitat
Enhancing natural resource conservation efforts
Fire management planning and modeling
Studying patterns of vegetation change over time
Managing invasive species
Land inventory and mapping programs
Setting national vegetation policies (e.g., biofuels, carbon markets, ecosystem services)
Developing national cropland statistics

Standard vs. Classification

The USNVC is structured by a data standard to create the vegetation hierarchy upon which the classification is generated.

The standard is the collective set of rules whose output describes the structure of the vegetation hierarchy. The end result of applying the standard is the classification or the fully listed vegetation hierarchy.

The National Vegetation Classification federal standard is a process standard. The standard itself does not contain a formal set of classification units, but rather outlines the process by which such units are to be described, peer-reviewed, and maintained through various data-management and web tools. This means that the classification is dynamic, subject to change as vegetation scientists revise, or newly describe vegetation types in the United States.